Cutting process is needed in order to dichotomize a wafer into chips. In a related art, blade sawing with the utilization of a diamond blade is typically performed. Wafer particles may occur during the cutting process when the blade is used. Further, supply of a cutting water to lower the temperature may be needed, and accordingly, a cleaning process may be needed. Also, there may be a high risk of damages to the patterns formed on the wafer during a physical cutting process.
Therefore, in order to remedy such shortcomings, cutting with the utilization of a laser recently has been used. Cutting with a may first involve a perforating process. The position of perforating focus with the utilization of the laser may be placed within the wafer. That is, the wafer may be divided into a plurality of dies by the process of passing through a surface of the wafer to perforate a hole within the wafer, and then by the chill and expander process.
At the above process, because the perforating position is placed within the wafer, such cutting process is named as “stealth cut” in view of it being unseen from the outside. The cutting process is similar to forming a crack.